The invention relates to apparatus for wrapping objects such as packs or bundles in a stretch foil, whereby the foil is drawn off from at least one delivery spool under tractive force and is then led around a winding cross-section. A transition conveyor is covered with foil and includes at least two conveyor belts arranged parallel one on top of the other. The lower one of these is designed as an actively driven conveyor belt with an outer side which is covered with the wrapping foil upon passing through the wrapping area, to form a tube of foil through which the objects to be wrapped pass. The upper conveyor belt is designed as a transport device for the packs of bundles.
Shaped, after-shrunk foils, i.e. so-called stretch foils, have made a far-reaching impact on wrapping technology in recent years. A feature of these foils is that an object wrapped in them is pressed together as a result of the remaining foil tension without the foil tearing. Thus, wrapping technology with the type of shaped, after-shrunk foil differs significantly from the using heat-shrunk foils.
In U.S. Pat. No. 4,050,220, an apparatus for wrapping packages is set forth with two conveyor belts arranged in a V-form for transporting objects to be wrapped to the wrapping station. Fixed guide rails are provided for the transport through the wrapping station. These guide rails are wrapped with foil, whereby the foil slides along the outer side of the guide rails as the packages move forward, and then slips off the guide rails at the end without any interruption. Because of the inherent tension, the foil then places itself onto the surface of the package units. The disadvantage of the fixed guide rails is that the foil clings to the guide rails as a results of the static electricity and cling effect, which then causes problems with the foil sliding off.
The concept set forth in U.S. Pat. No. 4,050,220, has been further developed (compare DE-OS No. 31 19 657). In the more advanced device, a transition conveyor has been provided which extends through the track of the winding tape lead apparatus and extends all the way through the lead apparatus without interruption. The transition conveyor consists of at least two conveyor bands arranged in a parallel position one above the other; the lower of these is designed as an actively driven conveyor with an outer side which is covered with the wrapping foil upon passage through the wrapping area, bringing the foil out. The upper conveyor belt is designed as a transport device for the packages. This permits a uniform forward movement of both packages and foil. The invention set forth here distinguishes itself from the familiar, above mentioned device.
In the apparatus described in DE-OS No. 31 19 657, the package units are always pushed in a certain direction through the wrapping in coils; thus, in the case of cartons loosely piled onto each other, which are to be grouped into a larger bundle, the positioning can slip and can even be grouped into a larger bundle, the positioning can slip and can even result in the dislodging of individual packages. In addition, a package unit can become damaged in its construction.